1
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Griffith EY, ElSayed M, Dura-Bernal S, Neymotin SA, Uhlrich DJ, Lytton WW, Zhu JJ. Mechanism of an Intrinsic Oscillation in Rat Geniculate Interneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.06.597830. [PMID: 38895250 PMCID: PMC11185623 DOI: 10.1101/2024.06.06.597830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Depolarizing current injections produced a rhythmic bursting of action potentials - a bursting oscillation - in a set of local interneurons in the lateral geniculate nucleus (LGN) of rats. The current dynamics underlying this firing pattern have not been determined, though this cell type constitutes an important cellular component of thalamocortical circuitry, and contributes to both pathologic and non-pathologic brain states. We thus investigated the source of the bursting oscillation using pharmacological manipulations in LGN slices in vitro and in silico. 1. Selective blockade of calcium channel subtypes revealed that high-threshold calcium currentsI L andI P contributed strongly to the oscillation. 2. Increased extracellular K+ concentration (decreased K+currents) eliminated the oscillation. 3. Selective blockade of K+ channel subtypes demonstrated that the calcium-sensitive potassium current (I A H P ) was of primary importance. A morphologically simplified, multicompartment model of the thalamic interneuron characterized the oscillation as follows: 1. The low-threshold calcium currentI T provided the strong initial burst characteristic of the oscillation. 2. Alternating fluxes through high-threshold calcium channels andI A H P then provided the continuing oscillation's burst and interburst periods respectively. This interplay betweenI L andI A H P contrasts with the current dynamics underlying oscillations in thalamocortical and reticularis neurons, which primarily involveI T andI H , orI T andI A H P respectively. These findings thus point to a novel electrophysiological mechanism for generating intrinsic oscillations in a major thalamic cell type. Because local interneurons can sculpt the behavior of thalamocortical circuits, these results suggest new targets for the manipulation of ascending thalamocortical network activity.
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Affiliation(s)
- Erica Y Griffith
- Department of Neural and Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, NY
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY
| | - Mohamed ElSayed
- Department of Psychiatry, Geisel School of Medicine at Dartmouth, Hanover, NH
- Department of Biomedical Engineering, SUNY Downstate School of Graduate Studies, Brooklyn, NY
- Department of Psychiatry, New Hampshire Hospital, Concord, NH
| | - Salvador Dura-Bernal
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY
| | - Samuel A Neymotin
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY
- Department of Psychiatry, New York University School of Medicine, New York, NY
| | - Daniel J Uhlrich
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
| | - William W Lytton
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY
- Department of Neurology, Kings County Hospital, Brooklyn, NY
| | - J Julius Zhu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
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2
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Zhou Y, Harvey PJ, Koehbach J, Chan LY, Jones A, Andersson Å, Vetter I, Durek T, Craik DJ. A Chemoenzymatic Approach To Produce a Cyclic Analogue of the Analgesic Drug MVIIA (Ziconotide). Angew Chem Int Ed Engl 2023; 62:e202302812. [PMID: 37148162 PMCID: PMC10952433 DOI: 10.1002/anie.202302812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/05/2023] [Accepted: 05/05/2023] [Indexed: 05/07/2023]
Abstract
Ziconotide (ω-conotoxin MVIIA) is an approved analgesic for the treatment of chronic pain. However, the need for intrathecal administration and adverse effects have limited its widespread application. Backbone cyclization is one way to improve the pharmaceutical properties of conopeptides, but so far chemical synthesis alone has been unable to produce correctly folded and backbone cyclic analogues of MVIIA. In this study, an asparaginyl endopeptidase (AEP)-mediated cyclization was used to generate backbone cyclic analogues of MVIIA for the first time. Cyclization using six- to nine-residue linkers did not perturb the overall structure of MVIIA, and the cyclic analogues of MVIIA showed inhibition of voltage-gated calcium channels (CaV 2.2) and substantially improved stability in human serum and stimulated intestinal fluid. Our study reveals that AEP transpeptidases are capable of cyclizing structurally complex peptides that chemical synthesis cannot achieve and paves the way for further improving the therapeutic value of conotoxins.
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Affiliation(s)
- Yan Zhou
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Peta J. Harvey
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Johannes Koehbach
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Lai Yue Chan
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Alun Jones
- Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Åsa Andersson
- Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Irina Vetter
- School of PharmacyInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - Thomas Durek
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
| | - David J. Craik
- ARC Centre of Excellence for Innovations in Peptide and Protein ScienceInstitute for Molecular BioscienceThe University of QueenslandBrisbaneQLD4072Australia
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3
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Chen J, Liu X, Yu S, Liu J, Chen R, Zhang Y, Jiang L, Dai Q. A novel ω-conotoxin Bu8 inhibiting N-type voltage-gated calcium channels displays potent analgesic activity. Acta Pharm Sin B 2021; 11:2685-2693. [PMID: 34589389 PMCID: PMC8463271 DOI: 10.1016/j.apsb.2021.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/13/2021] [Accepted: 03/01/2021] [Indexed: 01/11/2023] Open
Abstract
ω-Conotoxins inhibit N-type voltage-gated calcium (CaV2.2) channels and exhibit efficacy in attenuating neuropathic pain but have a low therapeutic index. Here, we synthesized and characterized a novel ω-conotoxin, Bu8 from Conus bullatus, which consists of 25 amino acid residues and three disulfide bridges. Bu8 selectively and potently inhibits depolarization-activated Ba2+ currents mediated by rat CaV2.2 expressed in HEK293T cells (IC50 = 89 nmol/L). Bu8 is two-fold more potent than ω-conotoxin MVIIA, a ω-conotoxin currently used for the treatment of severe chronic pain. It also displays potent analgesic activity in animal pain models of hot plate and acetic acid writhing but has fewer side effects on mouse motor function and lower toxicity in goldfish. Its lower side effects may be attributed to its faster binding rate and higher recovery ratios. The NMR structure demonstrates that Bu8 contains a small irregular triple β-strand. The structure-activity relationships of Bu8 Ala mutants and Bu8/MVIIA hybrid mutants demonstrate that the binding mode of CaV2.2 with the amino acid residues in loop 1 and loop 2 of Bu8 is different from that of MVIIA. This study characterizes a novel, more potent ω-conotoxin and provides new insights for designing CaV2.2 antagonists.
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Key Words
- Analgesic activity
- Bu8
- DIEA, diisopropylethylamine
- ESI-MS, electrospray ionization-mass spectroscopy
- Fmoc, N-(9-fluorenyl)methyloxy-carbonyl
- HBTU, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate
- HOBt, 1-hydroxybenzotriazole
- IC50, half-maximal inhibitory concentration
- N-type calcium ion channel
- RP-HPLC, reversed phase high-performance liquid chromatography
- Structure–activity relationship
- TFA, trifluoroacetic acid
- ω-conotoxin
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Affiliation(s)
- Jinqin Chen
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xinhong Liu
- Key Laboratory of Magnetic Resonance in Biological System, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuo Yu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Jia Liu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Rongfang Chen
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Yunxiao Zhang
- College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological System, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- Corresponding authors. Tel: +86 10 66948897.
| | - Qiuyun Dai
- Beijing Institute of Biotechnology, Beijing 100071, China
- Corresponding authors. Tel: +86 10 66948897.
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4
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Aridoss G, Kim D, Kim JI, Kang JE. Ziconotide (
ω‐conotoxin MVIIA
)—Efficient solid‐phase synthesis of a linear precursor peptide and its strategic native folding. Pept Sci (Hoboken) 2021. [DOI: 10.1002/pep2.24223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Gopalakrishnan Aridoss
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Dong‐Min Kim
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Jae Il Kim
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Jae Eun Kang
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
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5
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Discovery of a Novel Cysteine Framework XXIV Conotoxin from Conus striatus, S24a, with Potential Analgesic Activity. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-020-10109-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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6
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Sameera, Shah FA, Rashid S. Conformational ensembles of non-peptide ω-conotoxin mimetics and Ca +2 ion binding to human voltage-gated N-type calcium channel Ca v2.2. Comput Struct Biotechnol J 2020; 18:2357-2372. [PMID: 32994894 PMCID: PMC7498737 DOI: 10.1016/j.csbj.2020.08.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic neuropathic pain is the most complex and challenging clinical problem of a population that sets a major physical and economic burden at the global level. Ca2+-permeable channels functionally orchestrate the processing of pain signals. Among them, N-type voltage-gated calcium channels (VGCC) hold prominent contribution in the pain signal transduction and serve as prime targets for synaptic transmission block and attenuation of neuropathic pain. Here, we present detailed in silico analysis to comprehend the underlying conformational changes upon Ca2+ ion passage through Cav2.2 to differentially correlate subtle transitions induced via binding of a conopeptide-mimetic alkylphenyl ether-based analogue MVIIA. Interestingly, pronounced conformational changes were witnessed at the proximal carboxyl-terminus of Cav2.2 that attained an upright orientation upon Ca+2 ion permeability. Moreover, remarkable changes were observed in the architecture of channel tunnel. These findings illustrate that inhibitor binding to Cav2.2 may induce more narrowing in the pore size as compared to Ca2+ binding through modulating the hydrophilicity pattern at the selectivity region. A significant reduction in the tunnel volume at the selectivity filter and its enhancement at the activation gate of Ca+2-bound Cav2.2 suggests that ion binding modulates the outward splaying of pore-lining S6 helices to open the voltage gate. Overall, current study delineates dynamic conformational ensembles in terms of Ca+2 ion and MVIIA-associated structural implications in the Cav2.2 that may help in better therapeutic intervention to chronic and neuropathic pain management.
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Affiliation(s)
- Sameera
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fawad Ali Shah
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
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7
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Johnson MT, Gudlur A, Zhang X, Xin P, Emrich SM, Yoast RE, Courjaret R, Nwokonko RM, Li W, Hempel N, Machaca K, Gill DL, Hogan PG, Trebak M. L-type Ca 2+ channel blockers promote vascular remodeling through activation of STIM proteins. Proc Natl Acad Sci U S A 2020; 117:17369-17380. [PMID: 32641503 PMCID: PMC7382247 DOI: 10.1073/pnas.2007598117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Voltage-gated L-type Ca2+ channel (Cav1.2) blockers (LCCBs) are major drugs for treating hypertension, the preeminent risk factor for heart failure. Vascular smooth muscle cell (VSMC) remodeling is a pathological hallmark of chronic hypertension. VSMC remodeling is characterized by molecular rewiring of the cellular Ca2+ signaling machinery, including down-regulation of Cav1.2 channels and up-regulation of the endoplasmic reticulum (ER) stromal-interacting molecule (STIM) Ca2+ sensor proteins and the plasma membrane ORAI Ca2+ channels. STIM/ORAI proteins mediate store-operated Ca2+ entry (SOCE) and drive fibro-proliferative gene programs during cardiovascular remodeling. SOCE is activated by agonists that induce depletion of ER Ca2+, causing STIM to activate ORAI. Here, we show that the three major classes of LCCBs activate STIM/ORAI-mediated Ca2+ entry in VSMCs. LCCBs act on the STIM N terminus to cause STIM relocalization to junctions and subsequent ORAI activation in a Cav1.2-independent and store depletion-independent manner. LCCB-induced promotion of VSMC remodeling requires STIM1, which is up-regulated in VSMCs from hypertensive rats. Epidemiology showed that LCCBs are more associated with heart failure than other antihypertensive drugs in patients. Our findings unravel a mechanism of LCCBs action on Ca2+ signaling and demonstrate that LCCBs promote vascular remodeling through STIM-mediated activation of ORAI. Our data indicate caution against the use of LCCBs in elderly patients or patients with advanced hypertension and/or onset of cardiovascular remodeling, where levels of STIM and ORAI are elevated.
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Affiliation(s)
- Martin T Johnson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Aparna Gudlur
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Xuexin Zhang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Ping Xin
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Scott M Emrich
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Ryan E Yoast
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Raphael Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Robert M Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Wei Li
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Nadine Hempel
- Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Patrick G Hogan
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033;
- Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA 17033
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8
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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9
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Morales Duque H, Campos Dias S, Franco OL. Structural and Functional Analyses of Cone Snail Toxins. Mar Drugs 2019; 17:md17060370. [PMID: 31234371 PMCID: PMC6628382 DOI: 10.3390/md17060370] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/16/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022] Open
Abstract
Cone snails are marine gastropod mollusks with one of the most powerful venoms in nature. The toxins, named conotoxins, must act quickly on the cone snails´ prey due to the fact that snails are extremely slow, reducing their hunting capability. Therefore, the characteristics of conotoxins have become the object of investigation, and as a result medicines have been developed or are in the trialing process. Conotoxins interact with transmembrane proteins, showing specificity and potency. They target ion channels and ionotropic receptors with greater regularity, and when interaction occurs, there is immediate physiological decompensation. In this review we aimed to evaluate the structural features of conotoxins and the relationship with their target types.
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Affiliation(s)
- Harry Morales Duque
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
| | - Simoni Campos Dias
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
| | - Octávio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
- S-inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande-MS 79.117-900, Brazil.
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10
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Dong M, Wang F, Yan Z, Yu S, Wei J, Wu Q, Liu Z, Tang Y, Ding J, Dai Q. Structure-Activity Analysis of N-Type Calcium Channel Inhibitor SO-3. Biochemistry 2018; 57:6349-6355. [PMID: 30281282 DOI: 10.1021/acs.biochem.8b00803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
As an ω-conopeptide originally discovered from Conus striatus, SO-3 contains 25 amino acid residues and three disulfide bridges. Our previous study has shown that this peptide possesses potent analgesic activity in rodent pain models (mouse and rat), and it specifically inhibits an N-type calcium ion channel (Cav2.2). In the study presented here, we investigated the key amino acid residues for their inhibitory activity against Cav2.2 expressed in HEK 293 cells and analgesic activity in mice. To improve the inhibitory activity of SO-3, we also evaluated the effects of some amino acid residues derived from the corresponding residues of ω-peptide MVIIA, CVID, or GVIA. Our data reveal that Lys6, Ile11, and Asn14 are the important functional amino acid residues for SO-3. The replacement of some amino acid residues of SO-3 in loop 1 with the corresponding residues of CVID and GVIA improved the inhibitory activity of SO-3. The binding mode of Cav2.2 with SO-3 amino acids in loop 1 and loop 2 may be somewhat different from that of MVIIA. This study expanded our knowledge of the structure-activity relationship of ω-peptides and provided a new strategy for improving the potency of Cav2.2 inhibitors.
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Affiliation(s)
- Minxing Dong
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Fei Wang
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Zhenzhen Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Shuo Yu
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Juanjuan Wei
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Qiaoling Wu
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Zhuguo Liu
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Yifei Tang
- Beijing Institute of Biotechnology , Beijing 100071 , China
| | - Jiuping Ding
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Qiuyun Dai
- Beijing Institute of Biotechnology , Beijing 100071 , China
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11
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Sousa SR, McArthur JR, Brust A, Bhola RF, Rosengren KJ, Ragnarsson L, Dutertre S, Alewood PF, Christie MJ, Adams DJ, Vetter I, Lewis RJ. Novel analgesic ω-conotoxins from the vermivorous cone snail Conus moncuri provide new insights into the evolution of conopeptides. Sci Rep 2018; 8:13397. [PMID: 30194442 PMCID: PMC6128854 DOI: 10.1038/s41598-018-31245-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/07/2018] [Indexed: 12/28/2022] Open
Abstract
Cone snails are a diverse group of predatory marine invertebrates that deploy remarkably complex venoms to rapidly paralyse worm, mollusc or fish prey. ω-Conotoxins are neurotoxic peptides from cone snail venoms that inhibit Cav2.2 voltage-gated calcium channel, demonstrating potential for pain management via intrathecal (IT) administration. Here, we isolated and characterized two novel ω-conotoxins, MoVIA and MoVIB from Conus moncuri, the first to be identified in vermivorous (worm-hunting) cone snails. MoVIA and MoVIB potently inhibited human Cav2.2 in fluorimetric assays and rat Cav2.2 in patch clamp studies, and both potently displaced radiolabeled ω-conotoxin GVIA (125I-GVIA) from human SH-SY5Y cells and fish brain membranes (IC50 2–9 pM). Intriguingly, an arginine at position 13 in MoVIA and MoVIB replaced the functionally critical tyrosine found in piscivorous ω-conotoxins. To investigate its role, we synthesized MoVIB-[R13Y] and MVIIA-[Y13R]. Interestingly, MVIIA-[Y13R] completely lost Cav2.2 activity and MoVIB-[R13Y] had reduced activity, indicating that Arg at position 13 was preferred in these vermivorous ω-conotoxins whereas tyrosine 13 is preferred in piscivorous ω-conotoxins. MoVIB reversed pain behavior in a rat neuropathic pain model, confirming that vermivorous cone snails are a new source of analgesic ω-conotoxins. Given vermivorous cone snails are ancestral to piscivorous species, our findings support the repurposing of defensive venom peptides in the evolution of piscivorous Conidae.
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Affiliation(s)
- Silmara R Sousa
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Andreas Brust
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Rebecca F Bhola
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW, 2006, Australia
| | - K Johan Rosengren
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lotten Ragnarsson
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Sebastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier - CNRS, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France
| | - Paul F Alewood
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Macdonald J Christie
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW, 2006, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Irina Vetter
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,School of Pharmacy, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Richard J Lewis
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.
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12
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Fang GM, Chen XX, Yang QQ, Zhu LJ, Li NN, Yu HZ, Meng XM. Discovery, structure, and chemical synthesis of disulfide-rich peptide toxins and their analogs. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2018.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Gao B, Peng C, Yang J, Yi Y, Zhang J, Shi Q. Cone Snails: A Big Store of Conotoxins for Novel Drug Discovery. Toxins (Basel) 2017; 9:E397. [PMID: 29215605 PMCID: PMC5744117 DOI: 10.3390/toxins9120397] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/11/2022] Open
Abstract
Marine drugs have developed rapidly in recent decades. Cone snails, a group of more than 700 species, have always been one of the focuses for new drug discovery. These venomous snails capture prey using a diverse array of unique bioactive neurotoxins, usually named as conotoxins or conopeptides. These conotoxins have proven to be valuable pharmacological probes and potential drugs due to their high specificity and affinity to ion channels, receptors, and transporters in the nervous systems of target prey and humans. Several research groups, including ours, have examined the venom gland of cone snails using a combination of transcriptomic and proteomic sequencing, and revealed the existence of hundreds of conotoxin transcripts and thousands of conopeptides in each Conus species. Over 2000 nucleotide and 8000 peptide sequences of conotoxins have been published, and the number is still increasing quickly. However, more than 98% of these sequences still lack 3D structural and functional information. With the rapid development of genomics and bioinformatics in recent years, functional predictions and investigations on conotoxins are making great progress in promoting the discovery of novel drugs. For example, ω-MVIIA was approved by the U.S. Food and Drug Administration in 2004 to treat chronic pain, and nine more conotoxins are at various stages of preclinical or clinical evaluation. In short, the genus Conus, the big family of cone snails, has become an important genetic resource for conotoxin identification and drug development.
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Affiliation(s)
- Bingmiao Gao
- Hainan Provincial Key Laboratory of Research and Development of Tropical Medicinal Plants, Hainan Medical University, Haikou 571199, China.
| | - Chao Peng
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Jiaan Yang
- Micro Pharmtech, Ltd., Wuhan 430075, China.
| | - Yunhai Yi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
| | - Junqing Zhang
- Hainan Provincial Key Laboratory of Research and Development of Tropical Medicinal Plants, Hainan Medical University, Haikou 571199, China.
| | - Qiong Shi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
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Sensitive Detection of α-Conotoxin GI in Human Plasma Using a Solid-Phase Extraction Column and LC-MS/MS. Toxins (Basel) 2017; 9:toxins9080235. [PMID: 28788055 PMCID: PMC5577569 DOI: 10.3390/toxins9080235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 12/29/2022] Open
Abstract
α-conotoxin GI, a short peptide toxin in the venom of Conus geographus, is composed of 13 amino acids and two disulfide bonds. It is the most toxic component of Conus geographus venom with estimated lethal doses of 0.029–0.038 mg/kg for humans. There is currently no reported analytical method for this toxin. In the present study, a sensitive detection method was developed to quantify GI in human plasma using a solid-phase extraction (SPE) column (polystyrene–divinyl benzene copolymer) combined with liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the multiple reaction monitoring (MRM) mode. The plasma samples were treated with a protein precipitating solvent (methanol: acetonitrile = 50:50, v/v). GI in the solvent was efficiently extracted with an SPE column and was further separated by a Grace Alltima HP C18 (50 × 2.1 mm, 5 μm) column at a flow rate of 0.4 mL/min. Water (with 2% methanol) acetonitrile (with 0.1% acetic acid) was selected as the mobile phase combination used in a linear gradient system. α-Conotoxin GI was analyzed by an API 4000 triple quadrupole mass spectrometer. In the method validation, the linear calibration curve in the range of 2.0 to 300.0 ng/mL had correlation coefficients (r) above 0.996. The recovery was 57.6–66.8% for GI and the internal standard. The lower limit of quantification (LLOQ) was 2 ng/mL. The intra- and inter-batch precisions were below 6.31% and 8.61%, respectively, and the accuracies were all within acceptance. GI was stable in a bench-top autosampler through long-term storage and freeze/thaw cycles. Therefore, this method is specific, sensitive and reliable for quantitative analysis of α-conotoxin GI in human plasma.
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Yıldırım Ş, Öztürk Fincan GS, İşli F, Ercan S, Sarıoğlu Y. Effects of chronic l-DOPA administration on neurogenic and endothelium-dependent relaxation responses in rabbit corpus cavernosum. Pharmacol Rep 2016; 68:926-34. [PMID: 27362769 DOI: 10.1016/j.pharep.2016.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/09/2016] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Dopamine is a crucial central neurotransmitter that plays a fundamental role in the autonomic and somatic components of penile reflexes in animals and humans. Similar to the erectile responses of dopamine, systemic administration of l-DOPA induces yawning and penile erection in some species. The possible effects of l-DOPA on nitric oxide (NO)-dependent and -independent non-adrenergic non-cholinergic (NANC) relaxation responses mediated by electrical field stimulation (EFS) and endothelium-dependent relaxation were investigated in this study. METHODS Thirty-two adult albino male rabbits, in two- and four-week-treatment groups, were divided into three subgroups: control group (saline-injected) (n=4), 3mg/kg/day (low dose) l-DOPA-injected groups (n=6) and 12mg/kg/day (high dose) l-DOPA-injected groups (n=6). After the intraperitoneal injection treatments, the corpus cavernosum tissues were placed in organ bath chambers. The EFS-mediated responses, and the concentration-response curve to carbachol, sodium nitroprusside (SNP), sildenafil were assessed. RESULTS The two-week treatment with high-dose l-DOPA decreased the NO-dependent NANC relaxation responses, while there was no change in the low-dose two- and four-week treatment groups. The NO-independent NANC relaxation responses in the two-week groups decreased, and the responses in the four-week groups were unchanged when compared to the controls. The relaxation responses to carbachol showed no differences among all groups except for the high-dose four-week l-DOPA group. The relaxation responses of SNP and sildenafil were increased in all of the treatment groups when compared to the controls. CONCLUSIONS The observed increases in SNP- and sildenafil-induced responses, along with the decreased EFS-mediated responses, suggest increased sensitivity in the NO-signalling pathway following l-DOPA administration.
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Affiliation(s)
- Şeniz Yıldırım
- Department of Medical Pharmacology, Kırıkkale University, Kırıkkale, Turkey.
| | | | - Fatma İşli
- Department of Rational Drug Use and Supply Management, Turkish Medicines and Medical Devices Agency, Ministry of Health, Ankara, Turkey
| | - Sevim Ercan
- Member of Turkish Academy of Science, Turkey
| | - Yusuf Sarıoğlu
- Department of Medical Pharmacology, Gazi University, Ankara, Turkey
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16
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Bioactive Mimetics of Conotoxins and other Venom Peptides. Toxins (Basel) 2015; 7:4175-98. [PMID: 26501323 PMCID: PMC4626728 DOI: 10.3390/toxins7104175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/08/2015] [Indexed: 11/17/2022] Open
Abstract
Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties.
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Wang F, Yan Z, Liu Z, Wang S, Wu Q, Yu S, Ding J, Dai Q. Molecular basis of toxicity of N-type calcium channel inhibitor MVIIA. Neuropharmacology 2015; 101:137-45. [PMID: 26344359 DOI: 10.1016/j.neuropharm.2015.08.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 08/31/2015] [Accepted: 08/31/2015] [Indexed: 10/23/2022]
Abstract
MVIIA (ziconotide) is a specific inhibitor of N-type calcium channel, Cav2.2. It is derived from Cone snail and currently used for the treatment of severe chronic pains in patients unresponsive to opioid therapy. However, MVIIA produces severe side-effects, including dizziness, nystagmus, somnolence, abnormal gait, and ataxia, that limit its wider application. We previously identified a novel inhibitor of Cav2.2, ω-conopeptide SO-3, which possesses similar structure and analgesic activity to MVIIA's. To investigate the key residues for MVIIA toxicity, MVIIA/SO-3 hybrids and MVIIA variants carrying mutations in its loop 2 were synthesized. The substitution of MVIIA's loop 1 with the loop 1 of SO-3 resulted in significantly reduced Cav2.2 binding activity in vitro; the replacement of MVIIA loop 2 by the loop 2 of SO-3 not only enhanced the peptide/Cav2.2 binding but also decreased its toxicity on goldfish, attenuated mouse tremor symptom, spontaneous locomotor activity, and coordinated locomotion function. Further mutation analysis and molecular calculation revealed that the toxicity of MVIIA mainly arose from Met(12) in the loop 2, and this residue inserts into a hydrophobic hole (Ile(300), Phe(302) and Leu(305)) located between repeats II and III of Cav2.2. The combinative mutations of the loop 2 of MVIIA or other ω-conopeptides may be used for future development of more effective Cav2.2 inhibitors with lower side effects.
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Affiliation(s)
- Fei Wang
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Zhenzhen Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhuguo Liu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Sheng Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qiaoling Wu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Shuo Yu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Jiuping Ding
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Qiuyun Dai
- Beijing Institute of Biotechnology, Beijing 100071, China.
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18
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Arranz-Tagarro JA, de los Ríos C, García AG, Padín JF. Recent patents on calcium channel blockers: emphasis on CNS diseases. Expert Opin Ther Pat 2014; 24:959-77. [DOI: 10.1517/13543776.2014.940892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Chen R, Chung SH. Binding modes of two scorpion toxins to the voltage-gated potassium channel kv1.3 revealed from molecular dynamics. Toxins (Basel) 2014; 6:2149-61. [PMID: 25054783 PMCID: PMC4113748 DOI: 10.3390/toxins6072149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/08/2014] [Accepted: 07/10/2014] [Indexed: 12/13/2022] Open
Abstract
Molecular dynamics (MD) simulations are used to examine the binding modes of two scorpion toxins, margatoxin (MgTx) and hongotoxin (HgTx), to the voltage gated K+ channel, Kv1.3. Using steered MD simulations, we insert either Lys28 or Lys35 of the toxins into the selectivity filter of the channel. The MgTx-Kv1.3 complex is stable when the side chain of Lys35 from the toxin occludes the channel filter, suggesting that Lys35 is the pore-blocking residue for Kv1.3. In this complex, Lys28 of the toxin forms one additional salt bridge with Asp449 just outside the filter of the channel. On the other hand, HgTx forms a stable complex with Kv1.3 when the side chain of Lys28 but not Lys35 protrudes into the filter of the channel. A survey of all the possible favorable binding modes of HgTx-Kv1.3 is carried out by rotating the toxin at 3° intervals around the channel axis while the position of HgTx-Lys28 relative to the filter is maintained. We identify two possible favorable binding modes: HgTx-Arg24 can interact with either Asp433 or Glu420 on the vestibular wall of the channel. The dissociation constants calculated from the two binding modes of HgTx-Kv1.3 differ by approximately 20 fold, suggesting that the two modes are of similar energetics.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
| | - Shin-Ho Chung
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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20
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Akondi KB, Muttenthaler M, Dutertre S, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Discovery, synthesis, and structure-activity relationships of conotoxins. Chem Rev 2014; 114:5815-47. [PMID: 24720541 PMCID: PMC7610532 DOI: 10.1021/cr400401e] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | - Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
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21
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Koromyslova AD, Chugunov AO, Efremov RG. Deciphering fine molecular details of proteins' structure and function with a Protein Surface Topography (PST) method. J Chem Inf Model 2014; 54:1189-99. [PMID: 24689707 DOI: 10.1021/ci500158y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Molecular surfaces are the key players in biomolecular recognition and interactions. Nowadays, it is trivial to visualize a molecular surface and surface-distributed properties in three-dimensional space. However, such a representation trends to be biased and ambiguous in case of thorough analysis. We present a new method to create 2D spherical projection maps of entire protein surfaces and manipulate with them--protein surface topography (PST). It permits visualization and thoughtful analysis of surface properties. PST helps to easily portray conformational transitions, analyze proteins' properties and their dynamic behavior, improve docking performance, and reveal common patterns and dissimilarities in molecular surfaces of related bioactive peptides. This paper describes basic usage of PST with an example of small G-proteins conformational transitions, mapping of caspase-1 intersubunit interface, and intrinsic "complementarity" in the conotoxin-acetylcholine binding protein complex. We suggest that PST is a beneficial approach for structure-function studies of bioactive peptides and small proteins.
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Affiliation(s)
- Anna D Koromyslova
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences , 117997, Moscow, Russia
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22
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Hiersemenzel K, Brown ER, Duncan RR. Imaging large cohorts of single ion channels and their activity. Front Endocrinol (Lausanne) 2013; 4:114. [PMID: 24027557 PMCID: PMC3762133 DOI: 10.3389/fendo.2013.00114] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/16/2013] [Indexed: 01/16/2023] Open
Abstract
As calcium is the most important signaling molecule in neurons and secretory cells, amongst many other cell types, it follows that an understanding of calcium channels and their regulation of exocytosis is of vital importance. Calcium imaging using calcium dyes such as Fluo3, or FRET-based dyes that have been used widely has provided invaluable information, which combined with modeling has estimated the subtypes of channels responsible for triggering the exocytotic machinery as well as inferences about the relative distances away from vesicle fusion sites these molecules adopt. Importantly, new super-resolution microscopy techniques, combined with novel Ca(2+) indicators and imaginative imaging approaches can now define directly the nano-scale locations of very large cohorts of single channel molecules in relation to single vesicles. With combinations of these techniques the activity of individual channels can be visualized and quantified using novel Ca(2+) indicators. Fluorescently labeled specific channel toxins can also be used to localize endogenous assembled channel tetramers. Fluorescence lifetime imaging microscopy and other single-photon-resolution spectroscopic approaches offer the possibility to quantify protein-protein interactions between populations of channels and the SNARE protein machinery for the first time. Together with simultaneous electrophysiology, this battery of quantitative imaging techniques has the potential to provide unprecedented detail describing the locations, dynamic behaviors, interactions, and conductance activities of many thousands of channel molecules and vesicles in living cells.
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Affiliation(s)
- Katia Hiersemenzel
- Edinburgh Super-Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Euan R. Brown
- Edinburgh Super-Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Rory R. Duncan
- Edinburgh Super-Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
- *Correspondence: Rory R. Duncan, Edinburgh Super-Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK e-mail:
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Chen R, Chung SH. Complex structures between the N-type calcium channel (CaV2.2) and ω-conotoxin GVIA predicted via molecular dynamics. Biochemistry 2013; 52:3765-72. [PMID: 23651160 DOI: 10.1021/bi4003327] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The N-type voltage-gated Ca(2+) channel CaV2.2 is one of the important targets for pain management. ω-Conotoxins isolated from venoms of cone snails, which specifically inhibit CaV2.2, are promising scaffolds for novel analgesics. The inhibitory action of ω-conotoxins on CaV2.2 has been examined experimentally, but the modes of binding of the toxins to this and other related subfamilies of Ca(2+) channels are not understood in detail. Here molecular dynamics simulations are used to construct models of ω-conotoxin GVIA in complex with a homology model of the pore domain of CaV2.2. Three different binding modes in which the side chain of Lys2, Arg17, or Lys24 from the toxin protrudes into the selectivity filter of CaV2.2 are considered. In all the modes, the toxin forms a salt bridge with an aspartate residue of subunit II just above the EEEE ring of the selectivity filter. Using the umbrella sampling technique and potential of mean force calculations, the half-maximal inhibitory concentration (IC50) values are calculated to be 1.5 and 0.7 nM for the modes in which Lys2 and Arg17 occlude the ion conduction pathway, respectively. Both IC50 values compare favorably with the values of 0.04-1.0 nM determined experimentally. The similar IC50 values calculated for the different binding modes demonstrate that GVIA can inhibit CaV2.2 with alternative binding modes. Such a multiple-binding mode mechanism may be common for ω-conotoxins.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University , Canberra, ACT 0200, Australia
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24
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Bernáldez J, Román-González SA, Martínez O, Jiménez S, Vivas O, Arenas I, Corzo G, Arreguín R, García DE, Possani LD, Licea A. A Conus regularis conotoxin with a novel eight-cysteine framework inhibits CaV2.2 channels and displays an anti-nociceptive activity. Mar Drugs 2013; 11:1188-202. [PMID: 23567319 PMCID: PMC3705398 DOI: 10.3390/md11041188] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/05/2013] [Accepted: 03/18/2013] [Indexed: 12/22/2022] Open
Abstract
A novel peptide, RsXXIVA, was isolated from the venom duct of Conus regularis, a worm-hunting species collected in the Sea of Cortez, México. Its primary structure was determined by mass spectrometry and confirmed by automated Edman degradation. This conotoxin contains 40 amino acids and exhibits a novel arrangement of eight cysteine residues (C-C-C-C-CC-CC). Surprisingly, two loops of the novel peptide are highly identical to the amino acids sequence of ω-MVIIA. The total length and disulfide pairing of both peptides are quite different, although the two most important residues for the described function of ω-MVIIA (Lys2 and Tyr13) are also present in the peptide reported here. Electrophysiological analysis using superior cervical ganglion (SCG) neurons indicates that RsXXIVA inhibits CaV2.2 channel current in a dose-dependent manner with an EC50 of 2.8 μM, whose effect is partially reversed after washing. Furthermore, RsXXIVA was tested in hot-plate assays to measure the potential anti-nociceptive effect to an acute thermal stimulus, showing an analgesic effect in acute thermal pain at 30 and 45 min post-injection. Also, the toxin shows an anti-nociceptive effect in a formalin chronic pain test. However, the low affinity for CaV2.2 suggests that the primary target of the peptide could be different from that of ω-MVIIA.
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Affiliation(s)
- Johanna Bernáldez
- Molecular Immunology and Biotoxins Laboratory, Marine Biotechnology Department, Scientific Research and High Education Center from Ensenada (CICESE), Carretera Ensenada-Tijuana #3918, Zona Playitas, Ensenada 22860, Mexico; E-Mails: (J.B.); (O.M.); (S.J.)
| | - Sergio A. Román-González
- Chemistry Biomacromolecules Department, Chemistry Institute, National Autonomous University of Mexico, Av. Universidad 3000, Ciudad Universitaria, PO BOX 70-213, D.F. 04510, Mexico; E-Mails: (S.A.R.-G.); (R.A.)
| | - Oscar Martínez
- Molecular Immunology and Biotoxins Laboratory, Marine Biotechnology Department, Scientific Research and High Education Center from Ensenada (CICESE), Carretera Ensenada-Tijuana #3918, Zona Playitas, Ensenada 22860, Mexico; E-Mails: (J.B.); (O.M.); (S.J.)
| | - Samanta Jiménez
- Molecular Immunology and Biotoxins Laboratory, Marine Biotechnology Department, Scientific Research and High Education Center from Ensenada (CICESE), Carretera Ensenada-Tijuana #3918, Zona Playitas, Ensenada 22860, Mexico; E-Mails: (J.B.); (O.M.); (S.J.)
| | - Oscar Vivas
- Physiology Department, Medicine Faculty, National Autonomous University of Mexico, Av. Universidad 3000, Ciudad Universitaria, PO BOX 70-250, D.F. 04510, Mexico; E-Mails: (O.V.); (I.A.); (D.E.G.)
| | - Isabel Arenas
- Physiology Department, Medicine Faculty, National Autonomous University of Mexico, Av. Universidad 3000, Ciudad Universitaria, PO BOX 70-250, D.F. 04510, Mexico; E-Mails: (O.V.); (I.A.); (D.E.G.)
| | - Gerardo Corzo
- Department of Molecular Medicine and Bioprocesses, National Autonomous University of Mexico, Av. Universidad 2001, C.P. 510-3, Cuernavaca 61500, Mexico; E-Mails: (G.C.); (L.D.P.)
| | - Roberto Arreguín
- Chemistry Biomacromolecules Department, Chemistry Institute, National Autonomous University of Mexico, Av. Universidad 3000, Ciudad Universitaria, PO BOX 70-213, D.F. 04510, Mexico; E-Mails: (S.A.R.-G.); (R.A.)
| | - David E. García
- Physiology Department, Medicine Faculty, National Autonomous University of Mexico, Av. Universidad 3000, Ciudad Universitaria, PO BOX 70-250, D.F. 04510, Mexico; E-Mails: (O.V.); (I.A.); (D.E.G.)
| | - Lourival D. Possani
- Department of Molecular Medicine and Bioprocesses, National Autonomous University of Mexico, Av. Universidad 2001, C.P. 510-3, Cuernavaca 61500, Mexico; E-Mails: (G.C.); (L.D.P.)
| | - Alexei Licea
- Molecular Immunology and Biotoxins Laboratory, Marine Biotechnology Department, Scientific Research and High Education Center from Ensenada (CICESE), Carretera Ensenada-Tijuana #3918, Zona Playitas, Ensenada 22860, Mexico; E-Mails: (J.B.); (O.M.); (S.J.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +52-646-1750-500 (ext. 27201)
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Expression and pharmacology of endogenous Cav channels in SH-SY5Y human neuroblastoma cells. PLoS One 2013; 8:e59293. [PMID: 23536870 PMCID: PMC3607609 DOI: 10.1371/journal.pone.0059293] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 02/13/2013] [Indexed: 12/24/2022] Open
Abstract
SH-SY5Y human neuroblastoma cells provide a useful in vitro model to study the mechanisms underlying neurotransmission and nociception. These cells are derived from human sympathetic neuronal tissue and thus, express a number of the Cav channel subtypes essential for regulation of important physiological functions, such as heart contraction and nociception, including the clinically validated pain target Cav2.2. We have detected mRNA transcripts for a range of endogenous expressed subtypes Cav1.3, Cav2.2 (including two Cav1.3, and three Cav2.2 splice variant isoforms) and Cav3.1 in SH-SY5Y cells; as well as Cav auxiliary subunits α2δ1–3, β1, β3, β4, γ1, γ4–5, and γ7. Both high- and low-voltage activated Cav channels generated calcium signals in SH-SY5Y cells. Pharmacological characterisation using ω-conotoxins CVID and MVIIA revealed significantly (∼ 10-fold) higher affinity at human versus rat Cav2.2, while GVIA, which interacts with Cav2.2 through a distinct pharmacophore had similar affinity for both species. CVID, GVIA and MVIIA affinity was higher for SH-SY5Y membranes vs whole cells in the binding assays and functional assays, suggesting auxiliary subunits expressed endogenously in native systems can strongly influence Cav2.2 channels pharmacology. These results may have implications for strategies used to identify therapeutic leads at Cav2.2 channels.
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26
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Vink S, Alewood PF. Targeting voltage-gated calcium channels: developments in peptide and small-molecule inhibitors for the treatment of neuropathic pain. Br J Pharmacol 2013; 167:970-89. [PMID: 22725651 DOI: 10.1111/j.1476-5381.2012.02082.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Chronic pain affects approximately 20% of people worldwide and places a large economic and social burden on society. Despite the availability of a range of analgesics, this condition is inadequately treated, with complete alleviation of symptoms rarely occurring. In the past 30 years, the voltage-gated calcium channels (VGCCs) have been recognized as potential targets for analgesic development. Although the majority of the research has been focused on Ca(v) 2.2 in particular, other VGCC subtypes such as Ca(v) 3.2 have recently come to the forefront of analgesic research. Venom peptides from marine cone snails have been proven to be a valuable tool in neuroscience, playing a major role in the identification and characterization of VGCC subtypes and producing the first conotoxin-based drug on the market, the ω-conotoxin, ziconotide. This peptide potently and selectively inhibits Ca(v) 2.2, resulting in analgesia in chronic pain states. However, this drug is only available via intrathecal administration, and adverse effects and a narrow therapeutic window have limited its use in the clinic. Other Ca(v) 2.2 inhibitors are currently in development and offer the promise of an improved route of administration and safety profile. This review assesses the potential of targeting VGCCs for analgesic development, with a main focus on conotoxins that block Ca(v) 2.2 and the developments made to transform them into therapeutics.
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Affiliation(s)
- S Vink
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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Venom peptides as a rich source of cav2.2 channel blockers. Toxins (Basel) 2013; 5:286-314. [PMID: 23381143 PMCID: PMC3640536 DOI: 10.3390/toxins5020286] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/07/2013] [Accepted: 01/25/2013] [Indexed: 11/24/2022] Open
Abstract
Cav2.2 is a calcium channel subtype localized at nerve terminals, including nociceptive fibers, where it initiates neurotransmitter release. Cav2.2 is an important contributor to synaptic transmission in ascending pain pathways, and is up-regulated in the spinal cord in chronic pain states along with the auxiliary α2δ1 subunit. It is therefore not surprising that toxins that inhibit Cav2.2 are analgesic. Venomous animals, such as cone snails, spiders, snakes, assassin bugs, centipedes and scorpions are rich sources of remarkably potent and selective Cav2.2 inhibitors. However, side effects in humans currently limit their clinical use. Here we review Cav2.2 inhibitors from venoms and their potential as drug leads.
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Adams DJ, Callaghan B, Berecki G. Analgesic conotoxins: block and G protein-coupled receptor modulation of N-type (Ca(V) 2.2) calcium channels. Br J Pharmacol 2012; 166:486-500. [PMID: 22091786 DOI: 10.1111/j.1476-5381.2011.01781.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Conotoxins (conopeptides) are small disulfide bonded peptides from the venom of marine cone snails. These peptides target a wide variety of membrane receptors, ion channels and transporters, and have enormous potential for a range of pharmaceutical applications. Structurally related ω-conotoxins bind directly to and selectively inhibit neuronal (N)-type voltage-gated calcium channels (VGCCs) of nociceptive primary afferent neurones. Among these, ω-conotoxin MVIIA (Prialt) is approved by the Food and Drug Administration (FDA) as an alternative intrathecal analgesic for the management of chronic intractable pain, particularly in patients refractory to opioids. A series of newly discovered ω-conotoxins from Conus catus, including CVID-F, are potent and selective antagonists of N-type VGCCs. In spinal cord slices, these peptides reversibly inhibit excitatory synaptic transmission between primary afferents and dorsal horn superficial lamina neurones, and in the rat partial sciatic nerve ligation model of neuropathic pain, significantly reduce allodynic behaviour. Another family of conotoxins, the α-conotoxins, are competitive antagonists of mammalian nicotinic acetylcholine receptors (nAChRs). α-Conotoxins Vc1.1 and RgIA possess two disulfide bonds and are currently in development as a treatment for neuropathic pain. It was initially proposed that the primary target of these peptides is the α9α10 neuronal nAChR. Surprisingly, however, α-conotoxins Vc1.1, RgIA and PeIA more potently inhibit N-type VGCC currents via a GABA(B) GPCR mechanism in rat sensory neurones. This inhibition is largely voltage-independent and involves complex intracellular signalling. Understanding the molecular mechanisms of conotoxin action will lead to new ways to regulate VGCC block and modulation in normal and diseased states of the nervous system.
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Affiliation(s)
- David J Adams
- Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia.
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Jurkovičová-Tarabová B, Griesemer D, Pirone A, Sinnegger-Brauns MJ, Striessnig J, Friauf E. Repertoire of high voltage-activated Ca2+ channels in the lateral superior olive: functional analysis in wild-type, Cav1.3−/−, and Cav1.2DHP−/− mice. J Neurophysiol 2012; 108:365-79. [DOI: 10.1152/jn.00948.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Voltage-gated Ca2+ (Cav)1.3 α-subunits of high voltage-activated Ca2+ channels (HVACCs) are essential for Ca2+ influx and transmitter release in cochlear inner hair cells and therefore for signal transmission into the central auditory pathway. Their absence leads to deafness and to striking structural changes in the auditory brain stem, particularly in the lateral superior olive (LSO). Here, we analyzed the contribution of various types of HVACCs to the total Ca2+ current ( ICa) in developing mouse LSO neurons to address several questions: do LSO neurons express functional Cav1.3 channels? What other types of HVACCs are expressed? Are there developmental changes? Do LSO neurons of Cav1.3−/− mice show any compensatory responses, namely, upregulation of other HVACCs? Our electrophysiological and pharmacological results showed the presence of functional Cav1.3 and Cav1.2 channels at both postnatal days 4 and 12. Aside from these L-type channels, LSO neurons also expressed functional P/Q-type, N-type, and, most likely, R-type channels. The relative contribution of the four different subtypes to ICa appeared to be 45%, 29%, 22%, and 4% at postnatal day 12, respectively. The physiological results were flanked and extended by quantitative RT-PCR data. Altogether, LSO neurons displayed a broad repertoire of HVACC subtypes. Genetic ablation of Cav1.3 resulted in functional reorganization of some other HVACCs but did not restore normal ICa properties. Together, our results suggest that several types of HVACCs are of functional relevance for the developing LSO. Whether on-site loss of Cav1.3, i.e., in LSO neurons, contributes to the recently described malformation of the LSO needs to be determined by using tissue-specific Cav1.3−/− animals.
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Affiliation(s)
| | - Désirée Griesemer
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Antonella Pirone
- Institute of Physiology II and Department of Otolaryngology, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany; and
| | - Martina J. Sinnegger-Brauns
- Institute of Pharmacy, Pharmacology and Toxicology, Center of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Jörg Striessnig
- Institute of Pharmacy, Pharmacology and Toxicology, Center of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
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Pexton T, Moeller-Bertram T, Schilling JM, Wallace MS. Targeting voltage-gated calcium channels for the treatment of neuropathic pain: a review of drug development. Expert Opin Investig Drugs 2011; 20:1277-84. [DOI: 10.1517/13543784.2011.600686] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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31
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Kolosov A, Aurini L, Williams ED, Cooke I, Goodchild CS. Intravenous Injection of Leconotide, an Omega Conotoxin: Synergistic Antihyperalgesic Effects with Morphine in a Rat Model of Bone Cancer Pain. PAIN MEDICINE 2011; 12:923-41. [DOI: 10.1111/j.1526-4637.2011.01118.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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32
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Lee S, Kim Y, Back SK, Choi HW, Lee JY, Jung HH, Ryu JH, Suh HW, Na HS, Kim HJ, Rhim H, Kim JI. Analgesic effect of highly reversible ω-conotoxin FVIA on N type Ca2+ channels. Mol Pain 2010; 6:97. [PMID: 21172037 PMCID: PMC3025903 DOI: 10.1186/1744-8069-6-97] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Accepted: 12/21/2010] [Indexed: 11/10/2022] Open
Abstract
Background N-type Ca2+ channels (Cav2.2) play an important role in the transmission of pain signals to the central nervous system. ω-Conotoxin (CTx)-MVIIA, also called ziconotide (Prialt®), effectively alleviates pain, without causing addiction, by blocking the pores of these channels. Unfortunately, CTx-MVIIA has a narrow therapeutic window and produces serious side effects due to the poor reversibility of its binding to the channel. It would thus be desirable to identify new analgesic blockers with binding characteristics that lead to fewer adverse side effects. Results Here we identify a new CTx, FVIA, from the Korean Conus Fulmen and describe its effects on pain responses and blood pressure. The inhibitory effect of CTx-FVIA on N-type Ca2+ channel currents was dose-dependent and similar to that of CTx-MVIIA. However, the two conopeptides exhibited markedly different degrees of reversibility after block. CTx-FVIA effectively and dose-dependently reduced nociceptive behavior in the formalin test and in neuropathic pain models, and reduced mechanical and thermal allodynia in the tail nerve injury rat model. CTx-FVIA (10 ng) also showed significant analgesic effects on writhing in mouse neurotransmitter- and cytokine-induced pain models, though it had no effect on acute thermal pain and interferon-γ induced pain. Interestingly, although both CTx-FVIA and CTx-MVIIA depressed arterial blood pressure immediately after administration, pressure recovered faster and to a greater degree after CTx-FVIA administration. Conclusions The analgesic potency of CTx-FVIA and its greater reversibility could represent advantages over CTx-MVIIA for the treatment of refractory pain and contribute to the design of an analgesic with high potency and low side effects.
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Affiliation(s)
- Seungkyu Lee
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju, South Korea
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Nyce HL, Stober ST, Abrams CF, White MM. Mapping spatial relationships between residues in the ligand-binding domain of the 5-HT3 receptor using a molecular ruler. Biophys J 2010; 98:1847-55. [PMID: 20441748 DOI: 10.1016/j.bpj.2010.01.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/11/2010] [Accepted: 01/14/2010] [Indexed: 12/24/2022] Open
Abstract
The serotonin 5-HT(3) receptor (5-HT(3)R) is a member of the Cys-loop ligand-gated ion channel family. We used a combination of site-directed mutagenesis, homology modeling, and ligand-docking simulations to analyze antagonist-receptor interactions. Mutation of E236, which is near loop C of the binding site, to aspartate prevents expression of the receptor on the cell surface, and no specific ligand binding can be detected. On the other hand, mutation to glutamine, asparagine, or alanine produces receptors that are expressed on the cell surface, but decreases receptor affinity for the competitive antagonist d-tubocurarine (dTC) 5-35-fold. The results of a double-mutant cycle analysis employing a panel of dTC analogs to identify specific points of interactions between the dTC analogs and E236 are consistent with E236 making a direct physical interaction with the 12 -OH of dTC. dTC is a rigid molecule of known three-dimensional structure. Together with previous studies linking other regions of dTC to specific residues in the binding site, these data allow us to define the relative spatial arrangement of three different residues in the ligand-binding site: R92 (loop D), N128 (loop A), and E236 (near loop C). Molecular modeling employing these distance constraints followed by molecular-dynamics simulations produced a dTC/receptor complex consistent with the experimental data. The use of the rigid ligands as molecular rulers in conjunction with double-mutant cycle analysis provides a means of mapping the relative positions of various residues in the ligand-binding site of any ligand-receptor complex, and thus is a useful tool for delineating the architecture of the binding site.
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Affiliation(s)
- Heather L Nyce
- Department of Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Kamolkijkarn P, Prasertdee T, Netirojjanakul C, Sarnpitak P, Ruchirawat S, Deechongkit S. Synthesis, biophysical, and biological studies of wild-type and mutant psalmopeotoxins--anti-malarial cysteine knot peptides from Psalmopoeus cambridgei. Peptides 2010; 31:533-40. [PMID: 20067814 DOI: 10.1016/j.peptides.2010.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/03/2010] [Accepted: 01/03/2010] [Indexed: 10/20/2022]
Abstract
Psalmopeotoxin I and II (PcFK1 and PcFK2), an anti-malarial peptide first extracted from Psalmopoeus cambridgei was synthesized and characterized. Both peptides belong to the Inhibitor Cystine Knot (ICK) superfamily, containing three disulfide bridges. The six cysteine residues are conserved similar to other members of the ICK superfamily, suggesting their critical role for either folding or function. In this study, the peptides were synthesized using Fmoc solid-phase peptide synthesis (SPPS). The three disulfide bonds of were constructed by regioselective and random oxidative approaches. The resulting disulfide bond patterns were verified by the HPLC-MS analysis of intact peptides and by the disulfide bond mapping using tryptic digestion. Implications of the disulfide bonds on the biophysical and biological properties of PcFKs were studied using three disulfide mutants in which a particular pair of cysteines was replaced with two isosteric serine residues. Structures and biophysical characteristics of all variants were studied using far-UV CD and fluorescence spectroscopy. Biological activities of all variants were evaluated using antiplasmodial assay against the K1 multi-drug-resistant strain of P. falciparum. The experimental results showed that the three disulfide bridges could not be correctly synthesized by the random oxidative strategy. Structural and biophysical analyses revealed that all variants had similar structures to the twisted beta-sheet. However, the studies of disulfide bond removal indicated that each disulfide bond had different effects on both biophysical and biological activities of PcFKs. Correlation of biophysical parameters and biological activities showed that both PcFKs may have different mechanisms of actions for antiplasmodial activity.
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Affiliation(s)
- Pacharin Kamolkijkarn
- Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, Chemical Biology Program, Chulabhorn Graduate Institute, Bangkok 10210, Thailand
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Kolosov A, Goodchild CS, Cooke I. CNSB004 (Leconotide) Causes Antihyperalgesia Without Side Effects When Given Intravenously: A Comparison with Ziconotide in a Rat Model of Diabetic Neuropathic Pain. PAIN MEDICINE 2010; 11:262-73. [DOI: 10.1111/j.1526-4637.2009.00741.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bingham JP, Mitsunaga E, Bergeron ZL. Drugs from slugs--past, present and future perspectives of omega-conotoxin research. Chem Biol Interact 2010; 183:1-18. [PMID: 19800874 DOI: 10.1016/j.cbi.2009.09.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/03/2009] [Accepted: 09/24/2009] [Indexed: 12/18/2022]
Abstract
Peptides from the venom of carnivorous cone shells have provided six decades of intense research, which has led to the discovery and development of novel analgesic peptide therapeutics. Our understanding of this unique natural marine resource is however somewhat limited. Given the past pharmacological record, future investigations into the toxinology of these highly venomous tropical marine snails will undoubtedly yield other highly selective ion channel inhibitors and modulators. With over a thousand conotoxin-derived sequences identified to date, those identified as ion channel inhibitors represent only a small fraction of the total. Here we discuss our present understanding of conotoxins, focusing on the omega-conotoxin peptide family, and illustrate how such a seemingly simple snail has yielded a highly effective clinical drug.
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Affiliation(s)
- Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI 96822, USA.
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Berecki G, Motin L, Haythornthwaite A, Vink S, Bansal P, Drinkwater R, Wang CI, Moretta M, Lewis RJ, Alewood PF, Christie MJ, Adams DJ. Analgesic ω-Conotoxins CVIE and CVIF Selectively and Voltage-Dependently Block Recombinant and Native N-Type Calcium Channels. Mol Pharmacol 2009; 77:139-48. [DOI: 10.1124/mol.109.058834] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Conotoxins: molecular and therapeutic targets. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:45-65. [PMID: 19184584 DOI: 10.1007/978-3-540-87895-7_2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Marine molluscs known as cone snails produce beautiful shells and a complex array of over 50,000 venom peptides evolved for prey capture and defence. Many of these peptides selectively modulate ion channels and transporters, making them a valuable source of new ligands for studying the role these targets play in normal and disease physiology. A number of conopeptides reduce pain in animal models, and several are now in pre-clinical and clinical development for the treatment of severe pain often associated with diseases such as cancer. Less than 1% of cone snail venom peptides are pharmacologically characterised.
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Conotoxin Venom Peptide Therapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 655:44-8. [DOI: 10.1007/978-1-4419-1132-2_5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Hopping G, Lewis RJ, Alewood PF. Rapid Access to ω-Conotoxin Chimeras using Native Chemical Ligation. Aust J Chem 2009. [DOI: 10.1071/ch09216] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Grafting different regions of related peptides together to form a single protein chimera is a valuable tool in rapidly elucidating regions of activity or selectivity in peptides and proteins. To conveniently evaluate the contributions of the N- and C-terminal segments of ω-conotoxins CVID and MVIIC to activity, we employed native chemical ligation in CVID-MVIIC chimera design. Assembly of these peptide segments via the ligation method improved overall yield and coupling efficiency, with no difficult sequences encountered in contrast to the traditional full-length chain assembly of CVID. Radio-ligand binding assays revealed regions of importance for receptor recognition.
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Yao S, Zhang MM, Yoshikami D, Azam L, Olivera BM, Bulaj G, Norton RS. Structure, dynamics, and selectivity of the sodium channel blocker mu-conotoxin SIIIA. Biochemistry 2008; 47:10940-9. [PMID: 18798648 DOI: 10.1021/bi801010u] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
mu-SIIIA, a novel mu-conotoxin from Conus striatus, appeared to be a selective blocker of tetrodotoxin-resistant sodium channels in frog preparations. It also exhibited potent analgesic activity in mice, although its selectivity profile against mammalian sodium channels remains unknown. We have determined the structure of mu-SIIIA in aqueous solution and characterized its backbone dynamics by NMR and its functional properties electrophysiologically. Consistent with the absence of hydroxyprolines, mu-SIIIA adopts a single conformation with all peptide bonds in the trans conformation. The C-terminal region contains a well-defined helix encompassing residues 11-16, while residues 3-5 in the N-terminal region form a helix-like turn resembling 3 10-helix. The Trp12 and His16 side chains are close together, as in the related conotoxin mu-SmIIIA, but Asn2 is more distant. Dynamics measurements show that the N-terminus and Ser9 have larger-magnitude motions on the subnanosecond time scale, while the C-terminus is more rigid. Cys4, Trp12, and Cys13 undergo significant conformational exchange on microsecond to millisecond time scales. mu-SIIIA is a potent, nearly irreversible blocker of Na V1.2 but also blocks Na V1.4 and Na V1.6 with submicromolar potency. The selectivity profile of mu-SIIIA, including poor activity against the cardiac sodium channel, Na V1.5, is similar to that of the closely related mu-KIIIA, suggesting that the C-terminal regions of both are critical for blocking neuronal Na V1.2. The structural and functional characterization described in this paper of an analgesic mu-conotoxin that targets neuronal subtypes of mammalian sodium channels provides a basis for the design of novel analogues with an improved selectivity profile.
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Affiliation(s)
- Shenggen Yao
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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Duggan PJ, Faber JM, Graham JE, Lewis RJ, Lumsden NG, Tuck KL. Synthesis and Cav2.2 Binding Data for Non-Peptide Mimetics of ω-Conotoxin GVIA based on a 5-Amino-Anthranilamide Core. Aust J Chem 2008. [DOI: 10.1071/ch07327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A simple and efficient method has been developed for the synthesis of two anthranilamide-based non-peptide mimetics of ω-conotoxin GVIA. These anthranilamide derivatives aim to mimic the K2, R17, and Y13 residues of the peptide. The synthetic route described enables the rapid synthesis of anthranilamide analogues with identical alkyl chain lengths. The target compounds show affinity to rat N-type voltage gated calcium channels (Cav2.2) with EC50 values of 42 and 75 μM.
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Pluzhnikov K, Vassilevski A, Korolkova Y, Fisyunov A, Iegorova O, Krishtal O, Grishin E. ω-Lsp-IA, a novel modulator of P-type Ca2+ channels. Toxicon 2007; 50:993-1004. [PMID: 17888477 DOI: 10.1016/j.toxicon.2007.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2007] [Revised: 07/16/2007] [Accepted: 07/17/2007] [Indexed: 11/22/2022]
Abstract
A novel polypeptide, designated omega-Lsp-IA, which modulates P-type Ca(2+) channels, was purified from the venom of the spider Geolycosa sp. omega-Lsp-IA contains 47 amino acid residues and 4 intramolecular disulfide bridges. It belongs to a group of spider toxins affecting Ca(2+) channels and presumably forms the inhibitor cystine knot (ICK) fold. Peculiar structural features (a cluster of positively charged residues in the C-terminal loop of the peptide and a regular distribution of hydrophobic residues) that may play a decisive role in the omega-Lsp-IA mechanism of action were located. Recombinant omega-Lsp-IA was produced in prokaryotic expression system and was shown to be structurally and functionally identical to the native toxin. At saturating concentration (10nM), the peptide clearly slows down the activation kinetics and partially inhibits the amplitude of P-current in rat cerebellar Purkinje neurons. Prominent deceleration of the activation kinetics is manifested as the appearance of a five-fold slower component of the current activation. The specificity of action of omega-Lsp-IA on different Ca(2+) channel types was studied in isolated hippocampal neurons of rat. omega-Agatoxin IVA completely removed the effect of omega-Lsp-IA on the whole-cell Ca(2+) current. Therefore, omega-Lsp-IA appears to act specifically on P-type Ca(2+) channels.
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Affiliation(s)
- Kirill Pluzhnikov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya, 16/10, 117997 Moscow, Russian Federation
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Gasior M, White NA, Rogawski MA. Prolonged attenuation of amygdala-kindled seizure measures in rats by convection-enhanced delivery of the N-type calcium channel antagonists omega-conotoxin GVIA and omega-conotoxin MVIIA. J Pharmacol Exp Ther 2007; 323:458-68. [PMID: 17717191 PMCID: PMC2257985 DOI: 10.1124/jpet.107.125047] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Convection-enhanced delivery (CED) permits the homogeneous distribution of therapeutic agents throughout localized regions of the brain parenchyma without causing tissue damage as occurs with bolus injection. Here, we examined whether CED infusion of the N-type calcium channel antagonists omega-conotoxin GVIA (omega-CTX-G) and omega-conotoxin MVIIA (omega-CTX-M) can attenuate kindling measures in fully amygdala-kindled rats. Rats were implanted with a combination infusion cannula-stimulating electrode assembly into the right basolateral amygdala. Fully kindled animals received infusions of vehicle, omega-CTX-G (0.005, 0.05, and 0.5 nmol), omega-CTX-M (0.05, 0.15, and 0.5 nmol), proteolytically inactivated omega-CTX-M (0.5 nmol), or carbamazepine (500 nmol) into the stimulation site. CED of omega-CTX-G and omega-CTX-M over a 20-min period resulted in a dose-dependent increase in the afterdischarge threshold and a decrease in the afterdischarge duration and behavioral seizure score and duration during a period of 20 min to 1 week after the infusion, indicating an inhibitory effect on the triggering and expression of kindled seizures. The protective effects of omega-conotoxins reached a maximum at 48 h postinfusion, and then they gradually resolved over the next 5 days. In contrast, carbamazepine was active at 20 min but not at 24 h after the infusion, whereas CED of vehicle or inactivated omega-CTX-M had no effect. Except for transient tremor in some rats receiving the highest toxin doses, no adverse effects were observed. These results indicate that local CED of high-molecular-weight presynaptic N-type calcium channel blockers can produce long-lasting inhibition of brain excitability and that they may provide prolonged seizure protection in focal seizure disorders.
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Affiliation(s)
- Maciej Gasior
- Epilepsy Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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46
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Benjamin ER, Pruthi F, Olanrewaju S, Shan S, Hanway D, Liu X, Cerne R, Lavery D, Valenzano KJ, Woodward RM, Ilyin VI. Pharmacological characterization of recombinant N-type calcium channel (Cav2.2) mediated calcium mobilization using FLIPR. Biochem Pharmacol 2006; 72:770-82. [PMID: 16844100 DOI: 10.1016/j.bcp.2006.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Revised: 06/04/2006] [Accepted: 06/06/2006] [Indexed: 11/24/2022]
Abstract
The N-type voltage-gated calcium channel (Ca(v)2.2) functions in neurons to regulate neurotransmitter release. It comprises a clinically relevant target for chronic pain. We have validated a calcium mobilization approach to assessing Ca(v)2.2 pharmacology in two stable Ca(v)2.2 cell lines: alpha1(B), alpha2delta, beta(3)-HEK-293 and alpha1(B), beta(3)-HEK-293. Ca(v)2.2 channels were opened by addition of KCl and Ca(2+) mobilization was measured by Fluo-4 fluorescence on a fluorescence imaging plate reader (FLIPR(96)). Ca(v)2.2 expression and biophysics were confirmed by patch-clamp electrophysiology (EP). Both cell lines responded to KCl with adequate signal-to-background. Signals from both cell lines were inhibited by omega-conotoxin (ctx)-MVIIa and omega-conotoxin (ctx)-GVIa with IC(50) values of 1.8 and 1nM, respectively, for the three-subunit stable, and 0.9 and 0.6nM, respectively, for the two-subunit stable. Other known Ca(v)2.2 blockers were characterized including cadmium, flunarizine, fluspirilene, and mibefradil. IC(50) values correlated with literature EP-derived values. Novel Ca(v)2.2 pharmacology was identified in classes of compounds with other primary pharmacological activities, including Na(+) channel inhibitors and antidepressants. Novel Na(+) channel compounds with high potency at Ca(v)2.2 were identified in the phenoxyphenyl pyridine, phenoxyphenyl pyrazole, and other classes. The highest potency at Ca(v)2.2 tricyclic antidepressant identified was desipramine.
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Affiliation(s)
- Elfrida R Benjamin
- Purdue Pharma Discovery Research, 6 Cedarbrook Drive, Cranbury, NJ 08512, USA.
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Abstract
In the four decades since toxinologists in Australia and elsewhere started to investigate the active constituents of venomous cone snails, a wealth of information has emerged on the various classes of peptides and proteins that make their venoms such potent bioactive cocktails. This article provides an overview of the current state of knowledge of these venom constituents, several of which are of interest as potential human therapeutics as a consequence of their high potency and exquisite target specificity. With the promise of as many as 50,000 venom components across the entire Conus genus, many more interesting peptides can be anticipated.
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Affiliation(s)
- Raymond S Norton
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3050, Victoria, Australia.
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Yamazaki K, Shigetomi E, Ikeda R, Nishida M, Kiyonaka S, Mori Y, Kato F. Blocker-resistant presynaptic voltage-dependent Ca2+ channels underlying glutamate release in mice nucleus tractus solitarii. Brain Res 2006; 1104:103-13. [PMID: 16814754 DOI: 10.1016/j.brainres.2006.05.077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Revised: 05/20/2006] [Accepted: 05/24/2006] [Indexed: 11/17/2022]
Abstract
The visceral sensory information from the internal organs is conveyed via the vagus and glossopharyngeal primary afferent fibers and transmitted to the second-order neurons in the nucleus of the solitary tract (NTS). The glutamate release from the solitary tract (TS) axons to the second-order NTS neurons remains even in the presence of toxins that block N- and P/Q-type voltage-dependent Ca(2+) channels (VDCCs). The presynaptic VDCC playing the major role at this synapse remains unidentified. To address this issue, we examined two hypotheses in this study. First, we examined whether the remaining large component occurs through activation of a omega-conotoxin GVIA (omega-CgTX)-insensitive variant of N-type VDCC by using the mice genetically lacking its pore-forming subunit alpha(1B). Second, we examined whether R-type VDCCs are involved in transmitter release at the TS-NTS synapse. The EPSCs evoked by stimulation of the TS were recorded in medullary slices from young mice. omega-Agatoxin IVA (omega-AgaIVA; 200 nM) did not significantly affect the EPSC amplitude in the mice genetically lacking N-type VDCC. SNX-482 (500 nM) and Ni(2+) (100 microM) did not significantly reduce EPSC amplitude in ICR mice. These results indicate that, unlike in most of the brain synapses identified to date, the largest part of the glutamate release at the TS-NTS synapse in mice occurs through activation of non-L, non-P/Q, non-R, non-T and non-N (including its posttranslational variants) VDCCs at least according to their pharmacological properties identified to date.
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Affiliation(s)
- Koji Yamazaki
- Laboratory of Neurophysiology, Department of Neuroscience,The Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato, Tokyo 105-8461, Japan
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Millers EKI, Masci PP, Lavin MF, de Jersey J, Guddat LW. Crystallization and preliminary X-ray analysis of a Kunitz-type inhibitor, textilinin-1 from Pseudonaja textilis textilis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:642-5. [PMID: 16820682 PMCID: PMC2242938 DOI: 10.1107/s1744309106019099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 05/23/2006] [Indexed: 11/10/2022]
Abstract
Textilinin-1 (Txln-1), a Kunitz-type serine protease inhibitor, is a 59-amino-acid polypeptide isolated from the venom of the Australian Common Brown snake Pseudonaja textilis textilis. This molecule has been suggested as an alternative to aprotinin, also a Kunitz-type serine protease inhibitor, for use as an anti-bleeding agent in surgical procedures. Txln-1 shares only 47% amino-acid identity to aprotinin; however, six cysteine residues in the two peptides are in conserved locations. It is therefore expected that the overall fold of these molecules is similar but that they have contrasting surface features. Here, the crystallization of recombinant textilinin-1 (rTxln-1) as the free molecule and in complex with bovine trypsin (229 amino acids) is reported. Two organic solvents, phenol and 1,4-butanediol, were used as additives to facilitate the crystallization of free rTxln-1. Crystals of the rTxln-1-bovine trypsin complex diffracted to 2.0 angstroms resolution, while crystals of free rTxln-1 diffracted to 1.63 angstroms resolution.
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Affiliation(s)
- Emma-Karin I. Millers
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, QLD, Australia
| | - Paul P. Masci
- School of Medicine, Southern Division, University of Queensland, Princess Alexandra Hospital, Woolloongabba, Brisbane 4102, QLD, Australia
| | - Martin F. Lavin
- The Queensland Cancer Fund Research Unit, The Queensland Institute of Medical Research, PO Box, Royal Brisbane Hospital, Herston, Brisbane 4029, QLD, Australia
| | - John de Jersey
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, QLD, Australia
| | - Luke W. Guddat
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, QLD, Australia
- Correspondence e-mail:
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